1. Field of Invention
This invention relates generally to the field of medical instruments and more specifically to an ice dispenser for the application of cryotherapy or ice massage therapy to an injury.
2. Prior Art
The application of ice or other cold materials to an injury, known as cryotherapy, has long been used as an effective treatment for burns, bruises, arthritic joints and a variety of musculo-skeletal injuries, including sprains, strains, and fractures. It has also been found to be useful in the rehabilitation process after minor surgery, such as arthroscopic surgery. Generally, the goals of cryotherapy are to limit the formation of edema, to reduce pain, and to reduce muscle spasms. There are various types of devices, systems, and methods used today to apply cryotherapy including ice massage, ice immersion, cold whirlpools, ice bags, cold gel packs, cold chemical packs, and vapor-coolant sprays. In the past, ice massage was commonly applied with a piece of ice made by freezing a disposable paper or plastic cup filled with water. This method had several disadvantages. It was awkward and ineffective in that the user's hand was subjected to the low temperature of the frozen liquid. The heat of the user's hand also contributed to premature melting of the ice, thus lessening the useful life of the ice for treatment. Further, it was difficult to control the ice massage to the wounded area, since the cup began to collapse as the ice inside melted, offering a poor gripping surface. Furthermore, the ice would easily slip out of the cup and fall, becoming soiled and difficult to pick up and place back in the cup. Another method was to hold the piece of ice in a cloth. While initially helping to insulate the user's hand from the ice, the cloth quickly became wet from the melting ice, and the wet cloth would again transmit the cold to the user's hand. The use of a piece of cloth also made it difficult to control the pressure and location of the ice massage as it afforded an imprecise and loose grip on the ice.
An ice applicator for medicinal purposes by Hanson, et al. (U.S. Pat. No. 4,537,194 Aug. 27, 1985) uses a cup filled with water and a lid with an open top that engages the water when placed on the cup. When the cup and lid assembly are refrigerated, the resultant ice inside the cup forms with a mechanical attachment to the lid. The lid is then removed from the cup, pulling the ice with it, and acting as a handle for the ice.
A ball of ice gel by Bontemps (U.S. Pat. No. 5,127,395 Jul. 7, 1992) uses a hollow polyolefin sphere containing a frozen cooling mixture that is maintained at a temperature of about—20.degree C. The filled sphere functions to accumulate negative kilocalories and is manipulated by means of an isothermal plastic handle or sleeve in order to apply the sphere to the epidermis.
A treatment of vascular and tension headache, atypical facial pain, and cervical muscle hyperactivity by Friedman (U.S. Pat. No. 5,676,691 Oct. 14, 1997) uses plastic tubes encasing a column of ice, which ice can be extruded gradually by the patient or clinician by means of a plunger inserted into the tubes to apply ice to the area of tenderness associated with the plexus formed by the posterior superior alveolar branch of the ipsilateral maxillary nerve, as well as to other branches of the trigeminal nerve. Immediately preceding the application of the cold, an injection of a conventional dental anesthetic in the conventional amount used for that purpose could be made.